Treatment of bimetallic billets



o15,1946.` F. A. Ecm l A 2,409,422

Y ummm' Vo1 BIETALLIc BILLETS' Filed lay 26, 1942 Y-.Ifanczls E gan Y `Patented Oct. 15.1946

TREATMENT or BTMETALLIC BILLETS Francis A. Egan, Mount Lebanon, Pa., assignor to Superior Steel Corporation, Pittsburgh, Pa., a corporation of Virginia Application May 26, 1942, Serial No. 444,609

This invention relates to the treatment of bi` lthe treatment of bimetallic billets, will be described for purposes of explanation and illustraltion in connection with the treatment of a bimetallic billet comprising a steel backing or base `member faced on two opposite faces with gilding metal, the facing members being positioned and held in place on the backing member by ilanges of the backing member embracing the facing members. Bimetallic billets of this type are used to a great extent in the manufacture of bimetal- -lic strip for making ammunition components,

such, for example, as bullet jackets.

Different metals heated to a predetermined y temperature and hot rolled at that temperature elongate to different extents during hot rolling. When a plurality of `such metals are embodied in fthe same bimetallic billet as distinct billet components and the billet is heated and hot rolled the relatively more plastic metals will tend to elongate during hot rolling to an appreciably greater extent than the relatively less plastic metals. When a billet of the type above described comprising a steel backing member faced on opposte faces with gilding metal is heated to hot rolling temperature and hot rolled the gilding metalv facing members will, in the absence of counteractive treatment, elongate to a greater extent during hot rolling than the steel backing member. This is because gilding metal is more plastic at `hot rolling temperatures than steel.

` Gilding metal is composed of about 89 to 91% vcopper and about 9 to 11% zinc. Copper especially is now very scarce and in great demand for war purposes.` Thus it is extremely important to do away with any Wastage of gilding metal due to relatively great elongation during hot rolling of the gilding metal facing members of a bimetallic billet suchas above described. Moreover, the differential elongation of bimetallic billet components tends to interfere with proper bonding of the components during hot rolling.

3 claims. (ci. so-so) advantages above pointed out which have heretoforebeen encountered in the rolling of bimetallic billets. I control the relative elongation during hot rolling of the billet components of a bimetallic billet and I preferably provide for equal elongation of such components so that a billet having equally long components of relatively more plastic and relatively less plastic metals can be rolled in a hot rolling mill to produce hot rolled strip having both components of substantially the same length. VI control the extent to which the respective billet components elongate during the hot rolling by controlling their temperatures. By hot rolling the bimetallic billet with the relatively more plastic component at a lower temperature than the relatively less plastic component the tendency of the relatively more plastic component to elongate to a greater extent than the relatively less plastic component is counteracted. While the temperature control may be effected in various ways I prefer to first heat the bimetalllc billet to hot rolling temperature and then cool the relatively more plastic component. I prefer to spray the relatively more plastic component with a cooling medium. I nd that water is a satisfactory cooling medium for this purpose. The spraying of the relatively more plastic component or components of the billet lowers the temperature thereof relatively to the temeprature of the relatively less plastic component r components so that the billet can be rolled into a strip having all components of the same length, thus I provide for doing away with all of the dlseliminating Wastage at the ends of the strip. Moreover, by starting with a billet having the respective components of substantially Vthe same length and elongating the components together without substantial differential elongation any tendency of the components not to properly bond during hot rolling is minimized or entirely eliminated.

Other details, objects and advantages of the invention will become apparent as the following description of a present .preferred embodiment thereof and a present preferred method of practicing the same proceeds.

Inl the accompanying drawing I have shown a present preferred embodiment of the invention and have illustrated a present preferred method of practicing the same, in which Figure 1 is a side elevational view, partly in vertical longitudinal cross section, of apparatus for treating billets showing a billet being treated thereby; and

Figure 2 is a vertical transverse cross-sectional view taken on the line II--II of Figure 1.

the billet along over the rolls and turning the v rolls by the action of the billet thereagainst.

such as that in which it is shown in Figure 1 and there sprayed or it may be disposed in such 'position but moved back and forth slightly during spraying to insure cooling of the portions desired to be cooled.

As shown, the nozzles I6 and 2| preferably are elongated transversely of the roller table so that they emit a jet or spray which extends generally transversely of the work. The positions of the nozzles relatively to the bimetallic billets 4 are preferably adjusted so that the jet or spray from each nozzle will flare out transversely just sui- I preferably employ a roller table overfwhich the heated billets pass in their successive move.-- ment from the heating furnace to the rolling mill and I pro-vide means for acting on the billets while on the roller table. The billets may be acted on while moving on the -roller table' or they may be brought to a standstill while being actedon or they may be acted on partly while 'moving and partly while standing still. After they are acted`on they are advanced to the rolling mill and rolled in the usual way. A-

The roller table which I preferably employ comprises rollersA 2 having necks or axles 3, the

rollers being either driven rollers or idlers as desired. The billets passing from the heating funace to the rolling mill are supported upon and move over the rollers 2. One such billet is shown in the drawing, being designated generally by reference numeral 4. It comprises a steel body or backing member 5 having flanges 5 and facing members of gilding metal v designated by referencenumeral 'I held tothe backing member '5 bythe flanges 5. This form'of billet is now in 'regular use for making bimetallic strip. If the billet were rolled as delivered from the heating furnace the gliding metal facing. members l, being relatively more plastic-than the steel backing `5, would elongate during rolling to a greater extent than the backing member with the result that there would be a waste of the relatively 4expensive Copper alloy as well as a possible fail- 'ureof the billet components to properly bond during hot rolling due to the creeping action of the facing members relatively to the backing member. I provide cooling means for cooling the facing members so that they will be at a substantially lower temperature than the backing member when the billet enters the rolls of the rolling mill. Y

I provide a water supply pipe 8 which receives water atnormal temperature. The pipe 8 leads to a T 9 from which risers I0 and II extend upwardly and downwardly, respectively. The riser l5 communicates through an elbow l2 and a horizontal pipe I3 with a header I4 having a series of downwardly projecting pipes I5 each terminating in a nozzle I6. The riser II cornmunicates through an elbow I'I and a horizontal pipe I8 with a header I9 having a series of upwardly projecting pipes 2B each terminating in a nozze 2l. The nozzles 2I are disposed between the rollers 2 as shown. All of the nozzles are preferably directed toward the billet and also somewhat longitudinally to assist in spreading of the water over the surfaces of the billet to be cooled. The billet preferably moves from the heating furnace to the rolling mill in the direction from right to left viewing Figure l, and if the billet is sprayed while moving the directing of the jets in the direction opposite the direction of movement will assist in spreading the water over the surfaces to be cooled. However, the

billet may' be br'ought to a .stationary position fnace, resulting in controlled ciently to spray the full width of one of the gild- A11g .metal facing members 'I.

Thus the facing members will be sprayed and thus cooled while the backing `member' will not be directly sprayed except possibly for a little spray impinging upon the anges E, which will not materially affect the temperature of the backing member. The facing members are materially cooled by the spray so that during rolling their plasticity, and hence their elongation, will be "materially less than at the original higher temperature at 'which the entire billetY was delivered from the heating iurelongation of the respective billet components. The facing'members are preferably suiciently cooled that when the thus treated bimetallic billet is hot rolled the 'facing members land the backing member will elongate to the same extent.

While I have shown and described a present preferred embodiment of the invention and a present preferred method of practicing the same it is to be distinctly understood that the invention is ynot limited thereto but may be otherwise variously embodied and practiced within the scope-of the following claims.

1. A method of -treating a bimetallic billet havinga relatively less plastic component anda relatively more plastic component assembled together comprising heating the billet to bring it at Aleast to the 'hot rolling temperature of the 'relatively less plastic component, thereafter coolling-the relatively more plastic component so that the components areat such temperatures that vin h ot rolling they will both elongate to approximately the same length and hot rolling the thus 'prepared billet to elongate the same.

2'. A method of treating a bimetallidbillet 'having a relatively less plastic component and a 4relatively more plastic component assembled together comprising heating the billet to'bring it at least to the hot rolling temperature of the relatively less plastic component, thereafter spraying the relatively more plastic component 'to cool it so thatv the components are at such temperatures that in hot rolling they will both eongate to approximately the same length and hot rolling the thus prepared billet to elongate the same. f

3. A method of treating a bimetallic billet `having a relatively less plastic component and opposedA relatively more plastic components at opposite faces of the relatively less pasticcomponent, the components being assembled together,

comprising heating the billet to'bring it at least 'j t'o thehot rolling temperature of the relatively "less plastic component, thereafter cooling the relatively more plastic components so that the 'components are at such temperatures that in hot 'rolling they will all elongate to approximately the same length and hot rolling the thus prepared billet to elongate the same.

FRANCIS lA. Ecran 

